Tungsten or tungsten-based metals are used in gate electrode, wire, barrier layer or contact hole and via hole embodiment and the like of thin film transistors of liquid crystal displays and semiconductor devices. In addition, tungsten or tungsten-based metals are used as a tungsten heater in the field of micro electro mechanical systems (MEMS).
With the tungsten or the tungsten-based metals, titanium nitride (TiN), a titanium-based metal, is used as an underlayer or a cap layer of a precious metal, aluminum (Al) or copper (Cu) wire in semiconductor devices, liquid crystal displays, micro electro mechanical systems (MEMS) devices, print wiring boards and the like. In addition, titanium nitride is sometimes used as a barrier metal or a gate metal in semiconductor devices.
When forming both the tungsten and the titanium nitride to layers using CVD or sputtering, there is a problem in that, in semiconductor devices, the layers are attached to parts other than an actual device forming part, or the other side of a substrate (wafer), the edges of a substrate (wafer), an exterior wall of a layer forming device, inside an exhaust pipe or the like, and these are detached causing the generation of alien substances in the device forming part.
Particularly, a process of removing unnecessary parts leaving only tungsten or a tungsten alloy required for a device forming process of a semiconductor device such as a wire on a substrate or a via hole is required, and sometimes, a process removing all of tungsten or a tungsten alloy, or a barrier layer such as titanium nitride is used, however, depending on the properties of device preparation or depending on the properties of an etching solution, a process removing only tungsten or a tungsten alloy and suppressing the etching of a barrier layer such as titanium nitride, or, on the contrary, increasing the etching of titanium nitride while suppressing the etching of tungsten or a tungsten alloy is sometimes used. This is mostly due to the fact that semiconductor manufacturing processes are conducted considering properties of a device.
In such cases, properties of a device need to be obtained by selectively removing unnecessary parts in a device manufacturing process, and for such selective removal, a target layer needs to be selectively removed using an etching composition selective for tungsten or a tungsten layer, and a titanium nitride layer used as a material of a barrier layer.
In this case, tungsten or a tungsten alloy is preferably processed using wet etching having superior productivity rather than dry etching in processes for manufacturing semiconductor devices, liquid crystal displays, MEMS devices, print wiring boards and the like.
Korean Patent Application Laid-Open Publication No. 10-2011-0031233 discloses an existing etching solution for the wet etching. The etching solution is an etching solution using hydrogen peroxide, an organic acid salt and water, and etches titanium-based, tungsten-based, titanium-tungsten-based metals or nitrides thereof without etching Al, SiNx and the like, however, the etching composition selective for the metals has problems of causing hydrogen peroxide decomposition due to instability of the hydrogen peroxide, etching titanium and titanium nitride as well in addition to tungsten, and causing changes in the etch amount depending on the deposition time.
In addition, Japanese Patent Application Laid-Open Publication No. 2004-031443 discloses a composition polishing copper-based metals and titanium-based metals (including nitrides thereof) using a polishing solution containing an oxidizing agent, a dissolving agent for an oxidized metal, a metal corrosion preventing agent and water, and the polishing solution may have a problem of, in addition to the inconvenience coming from removing metals using a polishing method, a process increase in terms of going through a process of washing a substrate surface using a separate washing liquid in order to remove contaminated polished particles remaining on the substrate surface after being removed using the polishing method, and a cost increase, and in addition to these, has a problem of etching titanium and titanium nitride as well in addition to tungsten, and causing changes in the etch amount depending on the deposition time.
In view of the above, in the processes for manufacturing semiconductor devices, liquid crystal display devices and MEMS devices, development of etching solution compositions having smaller changes in the etch amount depending on the time of deposition in the etching solution composition while etching tungsten or a tungsten alloy without etching titanium nitride has been required.